382 The Ohio Naturalist. [Vol. VIII, No. 8, 



not far from the base. Middle coxae in the (5^ much thicker 

 than the hind coxae, trochantera convex and thicker than the 

 linear hind trochantera, femora hairless, slightly curved, incras- 

 saled towards the base, on the inner side with a spine a little 

 before the apex and a short spur just by the apex, tibiae very 

 strongly curved at the base with a tuft of short hairs on the inner 

 side of the end of the curve, between which point and the apex 

 the tibiae are straight and fringed with rather short straight 

 hairs on the outer side of the middle part. Hind legs in both 

 sexes simple, straight and hairless. pracposterus Bergr. 



The genital segments show much the same structure in all the 

 species. 



The following are the salient characters of the macropterous 

 form as represented by two winged specimens {(3^ 9 ) of Rh. ten- 

 uipes in my collection: Pronotum prolonged backward, cover- 

 ing the mesonotum, the posthumeral part forming a subtriangular 

 process with slightly rounded sides and rounded apex; a blunt 

 transversal keel between the humeri but not reaching them and 

 a median longitudinal impression between this keel and the pale 

 apical spot; an impressed line inside the lateral and posterior 

 margins. Scutellum half-concealed under the posterior end of 

 the pronotal process, blunt and callous at apex. Hemelytra very 

 much longer (d^) or moderately longer (9) than the abdomen; 

 corium membranous but well separated from the membrane, 

 greyish white, with brown veins, costal margin thickened, sub- 

 costal vein very fine, abbreviated towards the base, in the female 

 not discernible or coalescing with the costa, discal vein furcate 

 at apex, the short outer branch joining the costa a little before 

 its apex, the long inner branch running straight to the inner 

 apical angle joining the base of the inner vein of the membrane, 

 apical margin a little oblique, the outer apical angle slightly 

 obtuse, the inner slightly acute; clavus narrow but distinct 

 throughotit its length, greyish white with a short brown basal 

 vein barelv passing the apex of the scutellum ; membrane dis- 

 tinctly (c?) or slightly ( 9 ) longer than the corium, smoky, with 

 an outer and inner vein forming a loop and a median fold-like 

 greyish white vein. Wings considerably (cJ*) or a little (9) 

 longer than the abdomen, shorter than the hemelytra, smoky, 

 the veins arranged and colored as in the membrane. 



The veins of the corium are thus arranged much on the same 

 plan as in the genus Trepobates and those of the membrane are 

 practically identical in the two genera and very different from 

 the veins in the subfamily Gerrinae. 



I have not seen the winged form of Rh. Rileyi; a figure of it is 

 given as a frontispiece to the last parts of the Proc. Ent. Soc, 

 Washington. 



What Uhler describes as the "narrow, almost linear corium" 

 in the winged form of Rh. imitator is evidently not the -whole 

 corium, but only the space between the discal vein and -the 

 costa. 



